...Save our Soils
To mark World Soil Day, Professor Jane Rickson from Cranfield University outlines what we can do to preserve our soils, and how the CHAP Phenotyping and Soil Health Facility can help growers and food producers work towards healthier, stable and more productive soils.
1 Much more than ‘dirt’
Far from being just ‘dirt’, soil delivers a range of goods and services to society, including the production of food, fibre, fodder and fuel. Soils can receive, retain and release water, helping to combat floods (by absorbing storm water) and droughts (by storing rainfall and then releasing it to vegetation). Soils are also able to store vast amounts of carbon, helping to combat carbon emissions to the atmosphere and associated global warming, climate change and extreme weather events. Soils also provide habitats for organisms that underpin essential food chains. Soils also protect archaeological sites and support buildings and infrastructure.
2 Soil degradation processes
The ability of soil to deliver these essential goods and services to us is undermined by soil degradation processes. These have been identified as a ‘major threat to soil resources.’ The processes include soil erosion, compaction, loss of organic matter, loss of soil biodiversity, salinisation and acidification. These processes lead to land degradation, defined as ‘a negative trend in land condition, caused by direct or indirect human-induced processes, expressed as long-term reduction and as loss of at least one of the following: biological productivity, ecological integrity, or value to humans’ (IPCC 2019).
3 Costs of soil degradation
A study by Cranfield University has shown the total cost of soil degradation in England and Wales alone is £1.2 billion per annum. It is likely these costs will increase over time under future climate change scenarios. Global warming is also associated with more frequent, intense and longer duration rainfall events. High intensity rainfall increases the kinetic energy of the rainfall and its ability to cause erosion. Eroded material is then transferred off-site by surface runoff to watercourses, where excessive sediment can have negative ecological and environmental consequences on aquatic ecosystems.
4 Control of soil degradation
Soil degradation can be controlled through soil conservation measures. Farmers are using cover crops and crop residues to ensure soils are protected at all times from rainfall events. Field buffer strips are used to break up long slopes into shorter ones to reduce soil erosion. Erosion control geotextiles are used to protect bare soil, until an adequate vegetation cover can be established. Farmers have installed grassed waterways, which slow down the velocity of overland flow, encouraging the deposition of eroded soil within the channel, rather than letting it enter local watercourses. Farmers are also using less-intensive cultivations (such as zero tillage) that maintain soil structure and resist rainfall, runoff and wind.
5 Better understanding of soil degradation
CHAP’s unique Soil Health Facilities at Cranfield University improve our understanding of soil degradation processes and their control. The facilities include rainfall simulators that can accurately and reliably replicate rainfall events, from gentle ‘mizzle’ through to tropical thunderstorms. By measuring the amount of water and soil coming off the slope, we can evaluate different erosion control measures such as mulching, reduced tillage, cover crops and filter socks. The facilities can also be used to address a number of key soil and crop health challenges faced by the agricultural industry, namely:
- The effect of rainfall events on the rates of soil and water losses;
- The effect of rainfall intensity and soil surface sealing on seedling germination, emergence and growth; and
- The contamination of fresh produce (e.g. salad leaves) by rainsplash soil detachment.
Find out more about World Soil Day here…
